Automotive Air Conditioning Information Forum (Archives)

Provided by

We've updated our forums!
Click here to visit the new forum

Archive Home

Search Auto AC Forum Archives

Can I put mineral oil back in if ester was used in the past(R12 system)

bob234 on Tue August 24, 2010 2:08 AM User is offline

Year: 1993
Make: Chevrolet
Model: S10
Engine Size: 4.3
Refrigerant Type: R12

I am redoing the entire A/C in this truck as the previous owner half did it, and rigged many things up on it to make it work. It did have R12 in it, but he stuck a R134A retrofit adapter on the high side port instead of putting a new schrader in the R12 one. And the low pressure cut out switch was bad to he just connected the 2 wires together to make the compressor stay on. Well now that I had a shop evacuate the R12, I now have everything removed except the condenser and evaporator, and I took that R134A high side port off and fixed the R12 one. The old owner was using ester oil in it, because he converted to R134A in the past and said it didn't cool that great, so he put R12 back in without flushing, leaving the ester oil in. After I flush this system, would it be safe to put mineral oil back in, or would there be compatibility problems with residual ester?

Edited: Tue August 24, 2010 at 12:25 PM by bob234

Dave in Texas on Tue August 24, 2010 3:08 PM User is offlineView users profile

I'd use mineral oil. R12/mineral oil is a happy marriage. Ester is supposed to be compatible but after everything is flushed, there shouldn't be enough to measure. Ester is a synthetic while mineral is an organic.

At 2, I went home with a 10. At 10 I woke up with a 2 !!

mk378 on Tue August 24, 2010 3:43 PM User is offline

Well with a good flush there won't be any residual ester, but it's not going to cause problems to mix traces of one with the other-- either mineral in ester or ester in mineral.

Also it's good forum manners to bump up your old thread instead of starting new threads to discuss the same problem.

Back to Automotive Air Conditioning Forum

We've updated our forums!
Click here to visit the new forum

Archive Home

Copyright © 2016 Arizona Mobile Air Inc.